Salt and water imbalance in chronic heart failure

Renal Hemodynamics and Renin-Angiotensin-Aldosterone System Profiles in Patients With Heart Failure

OBJECTIVE

Understanding cardiorenal pathophysiology in heart failure (HF) is of clinical importance. We sought to characterize the renal hemodynamic function and the transrenal gradient of the renin-angiotensin-aldosterone system (RAAS) markers in patients with HF and in controls without HF.

METHODS

In this post hoc analysis, the glomerular filtration rate (GFR_inulin), effective renal plasma flow (ERPF_PAH) and transrenal gradients (arterial-renal vein) of angiotensin converting enzyme (ACE), aldosterone, and plasma renin activity (PRA) were measured in 47 patients with HF and in 24 controls. Gomez equations were used to derive afferent (R_A) and efferent (R_E) arteriolar resistances. Transrenal RAAS gradients were also collected in patients treated with intravenous dobutamine (HF, n = 11; non-HF, n = 11) or nitroprusside (HF, n = 18; non-HF, n = 5).

RESULTS

The concentrations of PRA, aldosterone and ACE were higher in the renal vein vs the artery in patients with HF vs patients without HF (P < 0.01). In patients with HF, a greater ACE gradient was associated with greater renal vascular resistance (r = 0.42; P 0.007) and greater arteriolar resistances (R_A: r = 0.39; P = 0.012; R_E: r = 0.48; P = 0.002). Similarly, a greater aldosterone gradient was associated with lower GFR (r = -0.51; P = 0.0007) and renal blood flow (RBF), r = -0.32; P = 0.042) whereas greater PRA gradient with lower ERPF (r = -0.33; P = 0.040), GFR (r = -0.36; P = 0.024), and RBF (r = -0.33; P = 0.036). Dobutamine and nitroprusside treatment decreased the transrenal gradient of ACE (P = 0.012, P < 0.0001, respectively), aldosterone (P = 0.005, P = 0.030) and PRA (P = 0.014, P = 0.002) in patients with HF only.

CONCLUSIONS

A larger transrenal RAAS marker gradient in patients with HF suggests a renal origin for neurohormonal activation associated with a vasoconstrictive renal profile.

Blood urea nitrogen to creatinine ratio is associated with congestion and mortality in heart failure patients with renal dysfunction

Renal dysfunction (RD) and venous congestion are related and common in heart failure (HF). Studies suggest that venous congestion may be the primary driver of RD in HF. In this study, we sought to investigate retrospectively the relationship between common measures of renal function with caval congestion and mortality among outpatients with HF and RD. We reviewed data from 103 HF outpatients (45 males, mean age 74 years, ejection fraction 41.8 ± 11.6 %) with estimated glomerular filtration rate (eGFR) of < 60 ml/min in a single centre. During an ambulatory visit, all patients underwent blood test and ultrasonography of the inferior vena cava (IVC). Caval congestion was defined as IVC with both dilatation and impaired collapsibility. The best values of renal metrics in predicting caval congestion were determined with receiver-operating characteristic analysis. The BUN/Cr ratio is moderately correlated with IVC expiratory maximum diameter (r = 0.31, p < 0.0007). In a multiple logistic regression model, BUN/Cr > 25.5 (adjusted OR 2.98, p 0.015) and eGFR ≤ 45.8 (adjusted OR 5.38, p 0.002) identify patients at risk for caval congestion; a BUN/Cr > 23.7 was the best predictor of impaired collapsibility (adjusted OR 4.41, p 0.001). a BUN/Cr > 25.5 (HR 2.19, 95 % CI 1.21-3.94, p < 0.001) and NYHA class 3 (HR 2.91, 95 % CI 1.60-5.31, p < 0.0005) were independent risk factors associated with all-cause death during a median follow-up of 31 months. In outpatients with HF and RD, a higher BUN/Cr and lower eGFR are reliable renal biomarkers for caval congestion. The BUN/Cr is associated with long-term mortality and may help to stratify HF severity.

Kidney disease in heart failure: the importance of novel biomarkers for type 1 cardio-renal syndrome detection

Chronic kidney disease (CKD) in heart failure (HF) has been recognized as an independent risk factor for adverse outcome, although the most important clinical trials tend to exclude patients with moderate and severe renal insufficiency. Despite this common association, the precise pathophysiological connection and liaison between heart and kidney is partially understood. Moreover, is it not enough considering how much cardio-renal syndrome type 1 is attributable to previous CKD, and how much to new-onset acute kidney injury (AKI). Neither development of AKI, its progression and time nor duration is related to an adverse outcome. An AKI definition is not universally recognized, and many confounding terms have been used in literature: "worsening renal function", "renal impairment", "renal dysfunction", etc., are all names that contribute to misunderstanding, and do not facilitate an universal classification. Therefore, AKI development should be the consequence of the basal clinical characteristics of patients, different primitive kidney disease and hemodynamic status. AKI could also be the mirror of several underlying associated diseases poorly controlled. Finally, it is not clear which is the optimal laboratory tool for identifying patients with an increased risk of AKI. In the current report, we review the different kidney diseases' impact in HF, and we analyze the modalities for AKI recognition during HF focusing our attention about some new biomarkers with potential application in the current setting.

Reduction of heart failure rehospitalization using a weight management education intervention

BACKGROUND

Previous investigators have demonstrated that patient adherence to optimal weight monitoring resulted in fewer heart failure (HF)-related rehospitalizations.

OBJECTIVE

The aim of this study was to determine whether a weight management (WM) intervention can improve patients' WM ability and cardiac function and reduce HF-related rehospitalizations.

METHODS

Heart failure patients were randomly assigned to an intervention group (n = 32) or a control group (n = 34). The intervention group received the WM intervention, including education about regular daily weight monitoring and coping skills when detecting sudden weight gain, with a WM booklet and scheduled telephone visits. Patients' WM ability was measured by the Weight Management Questionnaire (WMQ). We compared scores on the WMQ, New York Heart Association (NYHA) classification, and HF-related rehospitalizations between the 2 groups at enrollment and at 6 months. We also analyzed the association of adherence to weight monitoring and rehospitalization in the intervention group during the 6-month follow-up.

RESULTS

There were no significant differences in weight monitoring adherence, WM ability, and NYHA classification between the 2 groups at baseline. At 6 months, scores on all 4 subscales of the WMQ significantly increased within the intervention group, and the WM-practice subscale significantly improved within the control group. Adherence to weight monitoring was significantly improved in the intervention group compared with the control group (81.25% vs 11.76%; P < .01). At 6 months, there was a significant improvement in NYHA class in the intervention group compared with the control group (P = .03). Rehospitalizations related to HF were also fewer in the intervention group (0.28 ± 0.63 vs 0.79 ± 1.18; P = .03) during the follow-up duration. In the intervention group, those who weighed themselves regularly reported less HF-related rehospitalizations than did those who did not (0.23 ± 0.43 vs 0.50 ± 1.23; P = .62).

CONCLUSION

This study demonstrates that the WM intervention had a positive impact on patients' adherence to weight monitoring, WM ability, and NYHA classification and reduced HF-related rehospitalization.

Mineralocorticoid receptor in the NTS stimulates saline intake during fourth ventricular infusions of aldosterone

The purpose of this study was to determine whether neurons within the nucleus tractus solitarius (NTS) that express the mineralocorticoid receptor (MR) play a role in aldosterone stimulation of salt intake. Adult Wistar-Kyoto (WKY) rats received microinjections into the NTS of a short-hairpin RNA (shRNA) for the MR, to site specifically reduce levels of the MR by RNA interference (shRNA; n = 9) or scrambled RNA as a control (scRNA; n = 8). After injection of the viral construct, aldosterone-filled osmotic minipumps were implanted subcutaneously and connected to a cannula extending into the fourth ventricle to infuse aldosterone at a rate of 25 ng/h. Before and after surgeries, rats had ad libitum access to normal sodium (0.26%) rat chow and two graduated drinking bottles filled with either distilled water or 0.3 M NaCl. Before the surgeries, basal saline intake was 1.6 ± 0.6 ml in the scRNA group and 1.56 ± 0.6 ml in the shRNA group. Twenty-four days postsurgery, saline intake was elevated to a greater extent in the scRNA group (5.9 ± 1.07 ml) than in the shRNA group (2.41 ± 0.6 ml). Post mortem immunohistochemistry revealed a significant reduction in the number of NTS neurons exhibiting immunoreactivity for MR in shRNA-injected rats (23 ± 1 cells/section) versus scRNA-injected rats (33 ± 2 cells/section; P = 0.008). shRNA did not alter the level of 11-β-hydroxysteroid dehydrogenase type II (HSD2) protein in the NTS as judged by the number of HSD2 immunoreactive neurons. These results suggest that fourth ventricular infusions of aldosterone stimulate saline intake, and that this stimulation is at least in part mediated by hindbrain NTS neurons that express MR.